HyperCFD 3.5
Supersonic and Hypersonic Rocket Analysis

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Composite Plot Generated using AeroCFD

HyperCFD 3.5
Supersonic and Hypersonic Rocket Analysis using 3-D Gasdynamics
Determine drag coefficient (Cd), center of pressure (Xcp), CN-alpha and Cm-alpha of supersonic and hypersonic rockets and re-entry vehicles. In addition, on a separate screen HyperCFD displays and plots CN-Body, CN-Fins, CN-Total and Cm-Total as a function of angle of attack (AOA) using up/down controls. HyperCFD uses empirical aerodynamic corrections to the modified Newtonian surface inclination method that allows excellent results from Mach 1.05 to Mach 20. Includes a wide variety of nose cone shapes and fin cross-sections. Nose cone shapes include, conical, elliptical, parabolic, power series Sears-Haack, tangent ogive and spherical segment. Fin cross-sections include single wedge, symmetrical double wedge, arbitrary double wedge, biconvex section, streamline section, round-nose section, and elliptical section fin shapes. HyperCFD is useful to determine supersonic rocket drag and Cp location for level 3 flights.

New in this description is a methodology to determine thermal loads into the airframes of supersonic and hypersonic rockets using temperature distribution (T/Tinf) results from HyperCFD and AeroCFD.
In addition, a Microsoft Excel thermal analysis (50 KB) spreedsheet is available as a free download.

Also new in this description is a slender missile analysis that validates HyperCFD for the prediction of drag coefficient (Cd) and center of pressure location (XCp) for the flight regime which extends from Mach 1.05 to Mach 6.

The following links clearly illustrate how HyperCFD has been used to analyze re-entry vehicles.
Revisiting China’s Early Warhead Designs
Iranian Warhead Evolution


Standard HyperCFD Features
1) Temperature on the surface of the rocket relative to free-stream conditions.
2) Pressure and temperature can be output to a CSV format file and read as a text file or Excel spreadsheet.
3) Cd estimation as a function of AOA based on the Lester Lees modified Newtonian surface inclination theory.
4) Cd estimation and XCp estimation as a function of small angle of attack (1 to 2 degrees).
5) Cd estimation for decreasing cross-sectional components.
6) Display fin normal force coefficient (CN Fins), body normal force coefficient (CN Body), total normal force coefficient (CN Total) and total moment coefficient (CM Total) in addition to standard drag coefficients and center of pressure location in CSV format.
7) Plot shock wave shape and generate shock wave coordinates for sharp nose and blunt body projectiles.
8) Plot aerodynamic coefficients verses Mach number for Cd (subsonic, supersonic and hypersonic), XCp/L (Center of pressure location), CN (Normal force coefficient) and CM (Moment coefficient).
9) HyperCFD computes subsonic nose-body friction drag coefficien
t, nose-body base drag coefficient, fin surface drag coefficient, fin interference drag coefficient for laminar and turbulent flow based on NASA  high speed wind tunnel data.

The following shock wave values are displayed in the Rocket Geometry plot section
10a) Nose tip half-angle for attached shock or body half-angle after blunt nose for detached shock.
10b) Shock wave half-angle for attached (pointed nose) and detached (blunt nose) shock waves.
10c) Shock x-location from nose tip (Shock-x).


HyperCFD Results
Case #1: Re-Entry Vehicle


HyperCFD main screen displaying re-entry vehicle


HyperCFD re-entry vehicle pressure distribution


Case #2: Conical Nose Cone



Case #3: Missile With Fins

This section discusses the aerodynamic predictions, tests and analyses of a slender fin stabilized missile configuration for Mach numbers that range from 1.05 to 6. Prediction techniques consisted of both empirical and analytical methods, including a state-of-the-art computational fluid dynamics (CFD) code. Free flight tests in the USAF Aeroballistics Research Facility were conducted on sub-scale wind tunnel models to obtain an aerodynamic baseline to which the CFD predictions could be compared. This section summarizes these results and validates HyperCFD for the prediction of drag coefficient (Cd) and center of pressure location (Xcp) for the flight regime, which extends from Mach 1.05 to Mach 6. This section summarizes the results from the paper, Aerodynamic Test and Analysis of a Slender Generic Missile Configuration published by the AIAA Atmospheric Flight Mechanics Journal in 1989 and authored by John Cipolla.



Hypersonic missile In free flight as tested in the ARF


HyperCFD main screen displaying hypervelocity missile


Aerodynamic coefficients plotted using Cd vs Mn command button


HyperCFD fin geometry screen for hypervelocity missile


HyperCFD aerodynamic coefficients as a function of AOA on body, fins and fin-body


HyperCFD Motor On/Off screen



Free Flight data measured using the USAF Aeroballistic Research Facility (ARF)



Free-flight center of pressure location and drag coefficient of a slender missile with fins compared to HyperCFD.
Free Flight data from "Aerodynamic Test and Analysis of a Slender Generic Missile Configuration"; John Cipolla, AIAA.


Case #4: Biconic Re-Entry Vehicle

HyperCFD analysis of a Biconic re-entry vehicle operating at Mach 5 to determine Cd (drag coefficient), Xcp (center of pressure) and CNa (lift slope)


Case #5: Mars Phoenix Entry Capsule

AeroCFD used to generate a 3-D composite view of the Mars Phoenix entry capsule.



HyperCFD analysis of the Mars Phoenix entry capsule operating at Mach 18.5 to determine Cd, Xcp and CNa


Wall Temperature, Recovery Temperature and Airframe Thermal Loads

This is a simplified discussion of  the interaction between vehicle aerodynamics and heat loads on the airframe of a supersonic or hypersonic vehicle. First, the heating rate per area, q (W/m2) is defined as, q = k (Tr - Tw) where k is the convective heat transfer coefficient (W/m-K), Tr is the recovery or stagnation temperature, Tw is the wall temperature and r is the recovery factor which is equal to 1 for this example. Both temperatures are defined in degrees Kelvin (K). Wall temperature is computed using HyperCFD or AeroCFD and is derived from the ratio of T/Tinf where Tinf is the local atmospheric temperature and T is the wall temperature (Tw). The example below (second image) determines wall temperature, recovery temperature and maximum heat load into the airframe near the nose tip of a supersonic or hypersonic rocket. For this example Prandtl number (Pr) and recovery factor (r) both equal 1 and k = 151 W/m-K.

 
HyperCFD analysis of a hypersonic missile to determine airframe temperature distribution (T/Tinf)

DETERMINE WALL TEMPERATURE AND THERMAL LOAD
For a complete analysis download the free thermal analysis (50 KB)


Example to determine wall temperature, recovery temperature and airframe heat rate of a hypersonic rocket

SYSTEM REQUIREMENTS
(1) System: Windows 98, XP, Windows 7, 8, Windows 10 (32 bit and 64 bit), NT or Mac with emulation
(2) English (United States) Language
(3) 256 colors

PROGRAM REVISIONS
HyperCFD 3.5.0.1 (December 20, 2016)
1) Greatly enhanced computational speed for Windows 8, 10 and other enhancements. Verified compatibility with Windows 10.
2) Plot shock wave shape and generate shock wave coordinates for sharp nose and blunt body projectiles.
3) Plot aerodynamic coefficients verses Mach number for Cd (subsonic, supersonic and hypersonic), XCp/L (Center of pressure location), CN (Normal force coefficient) and CM (Moment coefficient).
4) HyperCFD computes subsonic nose-body friction drag coefficien
t, nose-body base drag coefficient, fin surface drag coefficient, fin interference drag coefficient for laminar and turbulent flow based on NASA high speed wind tunnel data.
The following shock wave values are displayed in the Rocket Geometry plot section
5a) Nose tip half-angle for attached shock or body half-angle after blunt nose for detached shock.
5b) Shock wave angle for a pointed nose OR shock wave angle of an equivalent pointed nose using blunt nose-body angle.
5c) Shock x-location from nose tip (Shock-x).

HyperCFD 3.5.0.2 and 3.5.0.3 (December 30, 2016)
1) Refined results of the shock wave shape analysis and fixed a few run time errors.

HyperCFD 3.5.0.4 (January 3, 2017)
1) Added background theory of attached shock waves and detached shock waves In the HyperCFD Instructions section.


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